Response by de Havenon et al to Letter Regarding Article, “Results From DEFUSE 3: Good Collaterals Are Associated With Reduced Ischemic Core Growth but Not Neurologic Outcome”

Abstract

We would like to thank Pirson et al. and Boulois et al. and for their letters in response to our article in Stroke entitled "Results from DEFUSE 3 Good Collaterals Are Associated with Reduced Ischemic Core Growth but Not Neurologic Outcome." 1 We believe that the surprising results of our pre-specified analysis of the DEFUSE 3 trial 2 warrant further discussion and welcome the opportunity to clarify several aspects of our article.

Displaying Multiphase CT Angiography Using a Time-Variant Color Map: Practical Considerations and Potential Applications in Patients with Acute Stroke

“…Good collaterals as determined on CTA have also been shown to correlate with reduced infarct volume in patients presenting beyond 6 hours. 1 Most interesting, no association between collateral status and outcome was noted in this study. 1 CTP, another imaging technique with time-resolved images of parenchymal blood flow but with more complex acquisition and postprocessing, is considered easier to interpret because the display format is a single color-coded cerebral map of estimated blood flow and predicted tissue fate.…”

“…1 Most interesting, no association between collateral status and outcome was noted in this study. 1 CTP, another imaging technique with time-resolved images of parenchymal blood flow but with more complex acquisition and postprocessing, is considered easier to interpret because the display format is a single color-coded cerebral map of estimated blood flow and predicted tissue fate. This feature is in spite of obvious disadvantages of CTP, including longer image-acquisition times, susceptibility to patient motion, more radiation exposure, an additional contrast dose, a lack of whole-brain coverage, and complex and heterogeneous postprocessing algorithms.…”

Hypoperfusion intensity ratio correlates with angiographic collaterals in acute ischaemic stroke with M1 occlusion

“…Patients with a robust filling of arteries distal to the site of occlusion on CTA are deemed to have favorable collaterals [25]. However, analyses based on CTA imaging do not provide information as to how much blood flows into the ischaemic tissue and this limitation may partially explain the heterogeneous response of patients with favorable CTA collaterals to EMT and the finding that the CTA collateral score did not predict outcomes in latewindow thrombectomy patients selected for treatment by CT or MR perfusion imaging [28]. Our results suggest that HIR and perfusion-based measures of collateral flow might be superior to angiographic measures of collaterals in early as well as late time windows [28] and future studies should test this hypothesis.…”

Actualización en diagnóstico y tratamiento del ataque cerebrovascular isquémico agudo

“…En cuanto a la circulación colateral, algunos estudios han mostrado que la presencia de buenas colaterales se asocia con mejor respuesta a la trombólisis, la terapia endovascular y la reducción del volumen del core isquémico (36); otros estudios apoyan que los pacientes con pobres colaterales están predispuestos a complicaciones hemorrágicas y muerte después de la terapia endovascular (37). Sin embargo, un reciente estudio en pacientes llevados a terapia endovascular con ventana mayor a 6 horas mostró que la presencia de buenas colaterales en angio-TAC solo se asoció con un volumen del core isquémico más pequeño y una reducción en su crecimiento; pero no influyó en desenlaces como independencia funcional medida por Rankin, ni en el éxito de la terapia endovascular o reducción en las complicaciones hemorrágicas o la muerte (38). Por lo anterior, si bien la circulación colateral puede proveer un flujo sanguíneo crucial en los pacientes con ACV (39), no debe ser un criterio único a la hora de incluir o excluir pacientes para realización de terapia trombolítica o endovascular.…”